Oxidation of Carbazole.

Abstract

In the oxidation of carbazole, two isomers of dicarbazyl are formed as main reaction products. 3, 3'-Dicarbazyl is formed by bichromate or permanganate oxidation in acetic acid, whereas 9, 9'-dicarbazyl is formed by permanganate oxida tion in acetone. It has thus been clarified that the formation of the two different isomers depends on the type of solvent rather than that of oxidant. The possibility that 3, 3'-dicarbazyl might be formed from the 9, 9'-isomer in glacial acetic acid through rearrangement has been eliminated. The results also indicate the absence of the N-acylation reaction on carbazole which impair the formation of 9, 9'-dicarbazyl. The ultraviolet spectra of carbazole solutions in hexane, ethanol, acetic acid, and dioxane indicated thot proton acceptors such as dioxane or acetone affected the electronic distribution on the carbazole molecule. The formation of 9, 9'-dicarbazyl may be explained by the induced changes in electronic distribution on the carba zole molecule.The structure of the 9, 9'-dimer has now been confirmed spectroscopically.